Endocrine, head & neck

Question 1

Differentiated thyroid cancer staging

Answer 1

TNM
T1a: <1cm
T1b: 1-2cm
T2: 2-4cm
T3a: > 4cm
T3b: Invasion of strap muscles
T4a: Invasion of subcutaneous soft tissues (larynx, trachea, oesophagus, RCN)
T4b: Invasion of prevertebral fascia or encasing carotid artery or mediastinal vessels
N0a: histology confirmed benign node
N0b: No clinical or radiological evidence of LN
N1a: Mets to level VI or VII nodes (pretracheal, paratracheal, prelaryngeal, upper mediastinal)
N1b: Mets to all other nodes or retropharyngeal nodes

Question 2

mutations associated with thyroid cancers

Answer 2

MTC:
- somatic RET mutation in 60%. Familial RET mutation in 25% (chromosome 10)

PTC
- MAPK pathway mutation (Most commonly BRAF V600E and RAS)

FTC
- RAS in 40%. PAX8-PPAR gamma 1
- Not assoc with BRAF

Hurtle Cell Cancer
- Mitochondrial DNA mutations and other randoms

Question 3

ATA risk factors

Answer 3

High risk (6):
- Macroscopic invasion into perithyroid soft tissues
- Incomplete resection with gross residual disease
- Distant mets
- Post-op Tg suggestive of distant mets
- Extranodal extension
Nodes >3cm in size
- Significant vascular invasion (>4 foci)

Intermediate risk
- Microscopic invasion into perithyroid soft tissues
- Cervical LN mets or iodine avid uptake in mets post RAI
- Tumour with aggressive histology (hobnail, tall cell, insular, columnar cell, Hurtle cell, follicular)
- > 5 nodes involved (<3cm diameter)
Multifocal Papillary microcarcinoma with ETE and BRAF V600E mutation

Low risk features
- No local or distant mets
- All macroscopic tumour resected
- No local invasion
- Non-aggressive histology
- No vascular invasion
- No iodine uptake on post ablation scan
- No LN mets, or <5 with micromets

Question 4

Indications for parathyroid surgery (consensus guidelines)

Answer 4

• Symptomatic
• Asymptomatic but with worsening biochemical markers
• Asymptomatic with one of the following
  Age < 50
  Ca > 0.25 ULN
  Renal failure eGFR < 60
  DEXA < -2.5 or osteoporotic fracture
  Renal stones

Question 5

Tirads criteria

Answer 5

Radiological scoring criteria to indicate risk of malingancy in a thyroid nodule and hence need for followup and biopsy. Based size, taller than wide, presence of calcifications, solid components, hypoechogenicity, margins
T1 - Normal thyroid gland. No biopsy
T2 - Benign nodule. No biopsy
T3 - Probably benign Biiopsy if > 2.5cm, follow if > 1.5cm. USS 2 years
T4 - Supciious for malignancy - Biopsy if >1.5cm. Follow if >1cm. USS 12-24 monhts
T5 - Highly suggestive of malingnacy. Biopsy if > 1cm, follow if > 0.5cm. USS 6-12 months

Question 6

Non-operative management of hyperparathyroidism

Answer 6

Conservative
-Adequate hydration
- Exercise to decrease bone resorption
- Avoiding exacerbating medicaitons (thiazides, lithium)
- Regular monitoring of renal function (yearly) + bone density (every 1-2 years)
Medications
- Calcimimetics (increase sensitivity of calcium sensing receptors on chief cells of PTH gland)
- Bisphosphonates